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revision 41 by nigel, Sat Feb 24 21:39:17 2007 UTC revision 167 by ph10, Wed May 9 15:53:54 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
4  A "configure" script is now used to configure PCRE for Unix systems. It builds  
5  a Makefile and a config.h file.  Release 7.2 30-Apr-07
6    ---------------------
8    Correction to the notes for 7.1: the note about shared libraries for Windows is
9    wrong. Previously, three libraries were built, but each could function
10    independently. For example, the pcreposix library also included all the
11    functions from the basic pcre library. The change is that the three libraries
12    are no longer independent. They are like the Unix libraries. To use the
13    pcreposix functions, for example, you need to link with both the pcreposix and
14    the basic pcre library.
16    Some more features from Perl 5.10 have been added:
18      (?-n) and (?+n) relative references for recursion and subroutines.
20      (Not sure if this one is actually in Perl 5.10)
21      (?(-n) and (?(+n) relative references as conditions.
24    Release 7.1 24-Apr-07
25    ---------------------
27    There is only one new feature in this release: a linebreak setting of
28    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
29    recognizes only CRLF, CR, and LF as linebreaks.
31    A few bugs are fixed (see ChangeLog for details), but the major change is a
32    complete re-implementation of the build system. This now has full Autotools
33    support and so is now "standard" in some sense. It should help with compiling
34    PCRE in a wide variety of environments.
36    NOTE: when building shared libraries for Windows, three dlls are now built,
37    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
38    included in a single dll.
40    Another important change is that the dftables auxiliary program is no longer
41    compiled and run at "make" time by default. Instead, a default set of character
42    tables (assuming ASCII coding) is used. If you want to use dftables to generate
43    the character tables as previously, add --enable-rebuild-chartables to the
44    "configure" command. You must do this if you are compiling PCRE to run on a
45    system that uses EBCDIC code.
47    There is a discussion about character tables in the README file. The default is
48    not to use dftables so that that there is no problem when cross-compiling.
51    Release 7.0 19-Dec-06
52    ---------------------
54    This release has a new major number because there have been some internal
55    upheavals to facilitate the addition of new optimizations and other facilities,
56    and to make subsequent maintenance and extension easier. Compilation is likely
57    to be a bit slower, but there should be no major effect on runtime performance.
58    Previously compiled patterns are NOT upwards compatible with this release. If
59    you have saved compiled patterns from a previous release, you will have to
60    re-compile them. Important changes that are visible to users are:
62    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
63       some more scripts.
65    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
66       sequence as a newline.
68    3. The \R escape matches a single Unicode newline sequence as a single unit.
70    4. New features that will appear in Perl 5.10 are now in PCRE. These include
71       alternative Perl syntax for named parentheses, and Perl syntax for
72       recursion.
74    5. The C++ wrapper interface has been extended by the addition of a
75       QuoteMeta function and the ability to allow copy construction and
76       assignment.
78    For a complete list of changes, see the ChangeLog file.
81    Release 6.7 04-Jul-06
82    ---------------------
84    The main additions to this release are the ability to use the same name for
85    multiple sets of parentheses, and support for CRLF line endings in both the
86    library and pcregrep (and in pcretest for testing).
88    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
89    significantly reduced for certain subject strings.
92    Release 6.5 01-Feb-06
93    ---------------------
95    Important changes in this release:
97    1. A number of new features have been added to pcregrep.
99    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
100       supported properties have been extended with script names such as "Arabic",
101       and the derived properties "Any" and "L&". This has necessitated a change to
102       the interal format of compiled patterns. Any saved compiled patterns that
103       use \p or \P must be recompiled.
105    3. The specification of recursion in patterns has been changed so that all
106       recursive subpatterns are automatically treated as atomic groups. Thus, for
107       example, (?R) is treated as if it were (?>(?R)). This is necessary because
108       otherwise there are situations where recursion does not work.
110    See the ChangeLog for a complete list of changes, which include a number of bug
111    fixes and tidies.
114    Release 6.0 07-Jun-05
115    ---------------------
117    The release number has been increased to 6.0 because of the addition of several
118    major new pieces of functionality.
120    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
121    algorithm, has been added. This has a number of advantages for certain cases,
122    though it does run more slowly, and lacks the ability to capture substrings. On
123    the other hand, it does find all matches, not just the first, and it works
124    better for partial matching. The pcrematching man page discusses the
125    differences.
127    The pcretest program has been enhanced so that it can make use of the new
128    pcre_dfa_exec() matching function and the extra features it provides.
130    The distribution now includes a C++ wrapper library. This is built
131    automatically if a C++ compiler is found. The pcrecpp man page discusses this
132    interface.
134    The code itself has been re-organized into many more files, one for each
135    function, so it no longer requires everything to be linked in when static
136    linkage is used. As a consequence, some internal functions have had to have
137    their names exposed. These functions all have names starting with _pcre_. They
138    are undocumented, and are not intended for use by outside callers.
140    The pcregrep program has been enhanced with new functionality such as
141    multiline-matching and options for output more matching context. See the
142    ChangeLog for a complete list of changes to the library and the utility
143    programs.
146    Release 5.0 13-Sep-04
147    ---------------------
149    The licence under which PCRE is released has been changed to the more
150    conventional "BSD" licence.
152    In the code, some bugs have been fixed, and there are also some major changes
153    in this release (which is why I've increased the number to 5.0). Some changes
154    are internal rearrangements, and some provide a number of new facilities. The
155    new features are:
157    1. There's an "automatic callout" feature that inserts callouts before every
158       item in the regex, and there's a new callout field that gives the position
159       in the pattern - useful for debugging and tracing.
161    2. The extra_data structure can now be used to pass in a set of character
162       tables at exec time. This is useful if compiled regex are saved and re-used
163       at a later time when the tables may not be at the same address. If the
164       default internal tables are used, the pointer saved with the compiled
165       pattern is now set to NULL, which means that you don't need to do anything
166       special unless you are using custom tables.
168    3. It is possible, with some restrictions on the content of the regex, to
169       request "partial" matching. A special return code is given if all of the
170       subject string matched part of the regex. This could be useful for testing
171       an input field as it is being typed.
173    4. There is now some optional support for Unicode character properties, which
174       means that the patterns items such as \p{Lu} and \X can now be used. Only
175       the general category properties are supported. If PCRE is compiled with this
176       support, an additional 90K data structure is include, which increases the
177       size of the library dramatically.
179    5. There is support for saving compiled patterns and re-using them later.
181    6. There is support for running regular expressions that were compiled on a
182       different host with the opposite endianness.
184    7. The pcretest program has been extended to accommodate the new features.
186    The main internal rearrangement is that sequences of literal characters are no
187    longer handled as strings. Instead, each character is handled on its own. This
188    makes some UTF-8 handling easier, and makes the support of partial matching
189    possible. Compiled patterns containing long literal strings will be larger as a
190    result of this change; I hope that performance will not be much affected.
193    Release 4.5 01-Dec-03
194    ---------------------
196    Again mainly a bug-fix and tidying release, with only a couple of new features:
198    1. It's possible now to compile PCRE so that it does not use recursive
199    function calls when matching. Instead it gets memory from the heap. This slows
200    things down, but may be necessary on systems with limited stacks.
202    2. UTF-8 string checking has been tightened to reject overlong sequences and to
203    check that a starting offset points to the start of a character. Failure of the
204    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
206    3. PCRE can now be compiled for systems that use EBCDIC code.
209    Release 4.4 21-Aug-03
210    ---------------------
212    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
213    checks UTF-8 strings for validity by default. There is an option to suppress
214    this, just in case anybody wants that teeny extra bit of performance.
217    Releases 4.1 - 4.3
218    ------------------
220    Sorry, I forgot about updating the NEWS file for these releases. Please take a
221    look at ChangeLog.
224    Release 4.0 17-Feb-03
225    ---------------------
227    There have been a lot of changes for the 4.0 release, adding additional
228    functionality and mending bugs. Below is a list of the highlights of the new
229    functionality. For full details of these features, please consult the
230    documentation. For a complete list of changes, see the ChangeLog file.
232    1. Support for Perl's \Q...\E escapes.
234    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
235    package. They provide some syntactic sugar for simple cases of "atomic
236    grouping".
238    3. Support for the \G assertion. It is true when the current matching position
239    is at the start point of the match.
241    4. A new feature that provides some of the functionality that Perl provides
242    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
243    is for the caller to provide an optional function, by setting pcre_callout to
244    its entry point. To get the function called, the regex must include (?C) at
245    appropriate points.
247    5. Support for recursive calls to individual subpatterns. This makes it really
248    easy to get totally confused.
250    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
251    name a group.
253    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
254    option for pcregrep to make it operate in UTF-8 mode.
256    8. The single man page has been split into a number of separate man pages.
257    These also give rise to individual HTML pages which are put in a separate
258    directory. There is an index.html page that lists them all. Some hyperlinking
259    between the pages has been installed.
262    Release 3.5 15-Aug-01
263    ---------------------
265    1. The configuring system has been upgraded to use later versions of autoconf
266    and libtool. By default it builds both a shared and a static library if the OS
267    supports it. You can use --disable-shared or --disable-static on the configure
268    command if you want only one of them.
270    2. The pcretest utility is now installed along with pcregrep because it is
271    useful for users (to test regexs) and by doing this, it automatically gets
272    relinked by libtool. The documentation has been turned into a man page, so
273    there are now .1, .txt, and .html versions in /doc.
275    3. Upgrades to pcregrep:
276       (i)   Added long-form option names like gnu grep.
277       (ii)  Added --help to list all options with an explanatory phrase.
278       (iii) Added -r, --recursive to recurse into sub-directories.
279       (iv)  Added -f, --file to read patterns from a file.
281    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
282    script, to force use of CR or LF instead of \n in the source. On non-Unix
283    systems, the value can be set in config.h.
285    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
286    absolute limit. Changed the text of the error message to make this clear, and
287    likewise updated the man page.
289    6. The limit of 99 on the number of capturing subpatterns has been removed.
290    The new limit is 65535, which I hope will not be a "real" limit.
293    Release 3.3 01-Aug-00
294    ---------------------
296    There is some support for UTF-8 character strings. This is incomplete and
297    experimental. The documentation describes what is and what is not implemented.
298    Otherwise, this is just a bug-fixing release.
301    Release 3.0 01-Feb-00
302    ---------------------
304    1. A "configure" script is now used to configure PCRE for Unix systems. It
305    builds a Makefile, a config.h file, and the pcre-config script.
307    2. PCRE is built as a shared library by default.
309    3. There is support for POSIX classes such as [:alpha:].
311    5. There is an experimental recursion feature.
313  ----------------------------------------------------------------------------  ----------------------------------------------------------------------------

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